It should be clear that all matter is made of atoms. From the
periodic table, it can be seen that there are only about 100 different
kinds of atoms in the entire Universe. These same 100 atoms form
thousands of different substances ranging from the air we breathe
to the metal used to support tall buildings. Metals behave differently
than ceramics, and ceramics behave differently than polymers.
The properties of matter depend on which atoms are used and how
they are bonded together.

The structure of materials can be classified by the general magnitude
of various features being considered. The three most common major
classification of structural, listed generally in increasing size,
are:

Atomic structure, which includes features that cannot be seen,
such as the types of bonding between the atoms, and the way the
atoms are arranged.
Microstructure, which includes features that can be seen using
a microscope, but seldom with the naked eye.
Macrostructure, which includes features that can be seen with
the naked eye)

The atomic structure primarily affects the chemical, physical,
thermal, electrical, magnetic, and optical properties. The microstructure
and macrostructure can also affect these properties but they generally
have a larger effect on mechanical properties and on the rate
of chemical reaction. The properties of a material offer clues
as to the structure of the material. The strength of metals suggests
that these atoms are held together by strong bonds. However, these
bonds must also allow atoms to move since metals are also usually
formable. To understand the structure of a material, the type
of atoms present, and how the atoms are arranged and bonded must
be known. Let’s first look at atomic bonding.